The present invention relates to a device for inspecting components and particularly to one using an array of light sources and video devices as a means of evaluating a component for conformance to spatial form criteria.
Presently, there is an ever increasing demand to obtain high quality products which has resulted in a significant increase in the use of non-contact inspection systems. In order for a complex machine to operate as designed, it is necessary that all of its sub-components comply with quality criteria. In some manufacturing settings, customers require 100% inspection of component parts. For example, fasteners used in the automobile industry and elsewhere often must be individually inspected to determine if they meet spatial form criteria.
Numerous types of inspection systems are presently utilized. One type of system uses contact probes which touch a component at various points to determine if its dimension or profile meet certain criteria. However, contact devices have inherent limitations in that they are subject to wear and generally require that the component and the contact probe be accurately positioned during the evaluation process. Moreover, such devices are generally slow to operate and are limited in terms of the number of criteria and complexity of profiles which they can evaluate. A variety of non-contact systems are also known using a variety of techniques. For example, ultrasonic inspection systems examine reflected sound waves as a means of characterizing a component. Various systems based on photodetection utilizing single channel photodetectors are also known. In addition, laser gauging systems are used in which specific dimensional measurements can be obtained.
However, although known non-contact inspection systems are generally extremely useful, they have certain limitations. Many of the presently available non-contact gauging systems require complex data processing approaches which impose speed limitations in part evaluations. For example, systems utilizing two-dimensional photosensitive arrays impose extreme data processing requirements, which has the effect of reducing part throughput. Preferably, evaluation of a workpiece can be conducted in a rapid enough fashion that the parts can be directly sorted into qualified or disqualified part streams. The systems which are capable of such high speed inspection lack valuable signal processing capabilities such as edge detection and real time imaging. Edge detection enhances the accuracy of the inspection enabling the parts inspection system to overcome the inherent limitations of discrete photodetectors. Early photodetection systems and ultrasonic systems provided part shape information based on the signal strength of a transducer. This information was only an approximation of the parts shape and not a true image of the part. For example single channel photodetectors could generate a single output related to the amount of occluded light. Over a set period of time this single channel photodetector gives an approximation of the part shape, but not an actual picture of the part. There is a need in the art for a high speed inspection system with powerful signal processing capabilities which include edge detection and real time imaging.